AI 中文总结
该研究提出太赫兹泵浦 - 拉曼探针法，用于绘制铌酸锂中声子极化激元色散图，可高精度提取频率和阻尼率的动量依赖性，通过理论与实验联合分析，揭示了声子本征阻尼率的非平凡频率依赖性及可能的非谐耦合。
AI 中文摘要
绘制极化激元（由光与物质耦合产生的混合准粒子）的色散图，可为材料介电响应、耦合强度以及与其他激发的能量转移途径提供关键见解。在这项工作中，我们提出太赫兹泵浦 - 拉曼探针（THz pump - Raman probe，TP - RP）作为一种通用方法，用于绘制极性非中心对称材料中的极化激元色散图，这里以铌酸锂中的声子极化激元为例进行说明。通过用宽带太赫兹泵浦共振驱动极化激元模式并用可调近红外拉曼脉冲进行探测，TP - RP能够高精度提取它们频率和阻尼率的动量依赖性。泵浦 - 探测信号中观察到的光谱特征，包括极化激元响应以及脉冲伪像，在多体理论方法中得以重现。将该技术应用于研究铌酸锂的E(TO₁)声子，能够通过理论与实验的联合分析揭示声子本征阻尼率的非平凡频率依赖性，揭示与其他模式可能的非谐耦合。
英文摘要
Mapping the dispersion of polaritons, hybrid quasiparticles arising from light-matter coupling, can provide key insights into the material dielectric response, coupling strength, and energy transfer pathways with other excitations. In this work, we present THz pump-Raman probe (TP-RP) as a versatile method for mapping the polariton dispersion in polar non-centrosymmetric materials, demonstrated here for the case of phonon-polaritons in LiNbO$_3$. By resonantly driving polaritonic modes with a broadband THz pump and probing them with a tunable NIR Raman pulse, TP-RP allows for the extraction of the momentum-dependence of both their frequency and damping rate with high accuracy. The spectral features observed in the pump-probe signal, including the polaritonic response as well as pulse artifacts, are reproduced within a many-body theoretical approach. Applying the technique to study the E(TO$_1$) phonon of LiNbO$_3$ enables the combined analysis of theory and experiments to uncover a nontrivial frequency dependence of the phonon intrinsic damping rate, revealing possible anharmonic couplings to other modes.
Comments29 pages, 13 figures
